Download Divisions of Skeleton - Van Buren Public Schools

I CAN…
…locate major bones in the human skeleton
…explain why there are 4 curves in the
human vertebral column
…compare and contrast bones of the axial and
appendicular skeleton
…explain why the bones of the foot are held
together by ligaments
…describe the differences between True Ribs,
False Ribs, and Floating Ribs
…describe the unique structure of the human
skull
I.
The Two Divisions of the Human Skeleton
A. The human skeleton is divided into the axial skeleton and
appendicular skeleton
Axial Skeleton – the bones of the head, neck and torso
Appendicular Skeleton – the bones of the upper and
lower extremities of the body
B. The bones of the axial skeleton are found in the: skull
(head), spine, chest, and the neck (hyoid bone)
The bones of the appendicular skeleton are found in the:
upper extremities (arms, elbow, wrists, & hands) and
lower extremities (legs, knee, ankle, & feet)
The Axial Skeleton
II.
A.
The skull is made up of 29 bones: (14.1% of total skeleton)
8 bones form the cranium, 14 bones form the face,
and 6 tiny bones (3 in each ear) form the middle ear
1. When people complain about their sinuses they are
complaining about: the spaces or cavities in the
cranial bones. SINUSITIS – inflammation of the
membranes of the sinuses.
Sinuses – a space or cavity inside the cranial bone
Paranasal sinuses – the four pairs of sinuses that
have openings into the nose
a. Frontal sinusitis occurs when the membranes lining the
frontal sinuses become inflammed (usually due to a
cold, allergies, environmental irritants, or bacterial
infection)
b. Mastoiditis occurs when bacterial cells from middle ear
infections find their way into the air spaces around the
mastoid process. It can lead to severe medical
problems if not treated because the infection can
spread to the brain (inflammatory exudate cannot
drain out of the nose)
2.
The different joints between the bones of the skull are
called sutures.
a. The sutures are located between the parietal bone
(which forms the characteristic bulge in the skull
topside) and the other bones of the skull
Lamboidal Suture between the parietal bone and
occipital bone
Squamous Suture between the parietal bone and the
temporal bone
Coronal Suture between the parietal bone and the
frontal bone
When a baby is born they have “ soft” spots on their
head from the areas where ossification in the skull is
incomplete after childbirth
*These soft spots will become ossified by the time the
baby is 2 yrs. old
3.
B.
The spine is also called the vertebral column and is made
up of 26 bones: (12.6% of the skeleton)
7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar
vertebrae, the sacrum, and the coccyx
1. The vertebral column is formed by a series of individual
irregular bones held in a series to form a flexible
curved rod.
2. The sections of the spine are named according to the
region of the body it is found in.
3. There are 4 prominent curves in the human spine: the
cervical curvature, thoracic curvature, lumbar
curvature, and pelvic (sacral) curvature.
When a newborn baby is born its spine is completely
convex. As it develops it learns to hold up its head
(cervical curve) and then learns to sit up (thoracic
curve) and then learns to stand (lumbar curve)
b. Throughout childhood, poor posture or disease may
cause the spine to curve abnormally. Sometimes these
abnormal curvatures may affect the permanent
posture of the individual.
Lordosis – abnormally exaggerated lumbar curvature
of the vertebral column
Kyphosis – abnormally exaggerated thoracic curvature
of the vertebral column
Scoliosis –abnormal LATERAL curvature of the
vertebral column
a.
1) Treatments of scoliosis include:
1. Milwaukee Brace: worn every day for 23 hours.
Treatment may last several years. The brace has
pads that push against the curves in the spine to
prevent further curvature.
2. Transcutaneous Muscle Stimulation: muscles are
electrically stimulated on one side to contract and
straighten the muscles supporting the vertebral
column
3. Surgery: chips of bone are grafted to the curved
vertebrae to hold them in a normal position.
C.
The thorax is made up of 25 bones: (12.1% of the skeleton)
14 true ribs, 10 False Ribs, and 1 sternum
1. True Ribs: The 1st 7 pairs of ribs are attached posteriorly
and anteriorly to the sternum by costal cartilage.
False Ribs: The 8th, 9th, and 10th pairs of ribs are attached
to the cartilage of the 7th pair.
Floating Ribs: The 11th and 12th pairs are not attached to
anything anteriorly.
III.
A.
B.
Appendicular Skeleton
Out of the 206 bones in the human body 126 are found in
the appendicular subdivision. (61.1% of the skeleton)
The upper extremities are attached to the axial skeleton
at the pectoral girdle. (the pectoral girdle is made up of
the scapula and clavicle)
Sternoclavicular joint – the direct point of attachment
between the bones of the upper extremity and the
axial skeleton
The Sternoclavicular joint is part
of the appendicular subdivision
C.
The bones of the arm are: the humerus (upper arm),
the radius, and the ulna
Humerus – the second largest bone in the body; the
long bone of the arm
Radius – one of the two bones of the forearm; located
on the thumb side of the forearm
Ulna – one of the two bones in the forearm; located
on the little finger side of the forearm
1. The radius and the ulna
1. articulate w/ each other and the humerus at the
elbow
2. articulate w/ each other and the bones in the
wrist.
D.
The many bones of the hand and wrist make the
human hand highly maneuverable
(makes humans more advanced than other
creatures)
E.
The bones of the leg are attached to the axial skeleton at
the hip/pelvic girdle.
The pelvic girdle is
a part of the
appendicular
subdivison
1. The different bones of the leg are: femur, tibia,
and the fibula
F.
Femur – the thigh bone, which is the longest bone in the
human body
Fibula – the slender non-weight bearing bone located on
the lateral aspect of the leg
Tibia – shin bone
The bones in the feet are named using similar names as
the bones in the hands
fingers/toes = phalanges/phalanges
hands(wrists)/feet(ankle) =
metacarpals(carpals)/metatarsals(tarsals)
1.



Differences between the hand and feet include:
Foot only has 7 tarsals, the hand has 8 carpals
Hand has more movement at the wrist
Saddle joint at the distal trapezium (where the 1st
metacarpal meets the carpal) allows the hand to
grip objects
2. The foot bones are held together so that they can
support the body’s weight. The bones form
“springy” lengthwise and crosswise arches. Strong
ligaments and tendons hold the bones in the arched
position. If the ligaments and tendons weaken the
arches can fall = “fallen arches”
Medial longitudinal arch – lengthwise arch that lies
along the inside part of the foot
Lateral longitudinal arch – lengthwise arch that lies
along the outer edge of the foot
Transverse (metatarsal) arch – crosswise arch that
extends across the ball of the foot